when.md

This is RxJS v 4. Find the latest version here

Rx.Observable.when(...args)

Ⓢ

A series of plans (specified as an Array or as a series of arguments) created by use of the Then operator on patterns.

Arguments

1. args (arguments|Array): A series of plans (specified as an Array of as a series of arguments) created by use of the then operator on patterns.

Returns

(Observable): Observable sequence with the results form matching several patterns.

Example

// Fire each plan when both are ready
var source = Rx.Observable.when(
  Rx.Observable.timer(100).and(Rx.Observable.timer(500)).thenDo(function (x, y) { return 'first'; }),
  Rx.Observable.timer(400).and(Rx.Observable.timer(300)).thenDo(function (x, y) { return 'second'; })
);

var subscription = source.subscribe(
  function (x) {
      console.log('Next: ' + x);
  },
  function (err) {
      console.log('Error: ' + err);
  },
  function () {
      console.log('Completed');
  });

// => Next: second
// => Next: first
// => Completed

Example

var chopsticks = [new Rx.Subject(), new Rx.Subject(), new Rx.Subject()];

var hungry = [new Rx.Subject(), new Rx.Subject(), new Rx.Subject()];

var eat = i => {
  return () => {
    setTimeout(() => {
      console.log('Done');
      chopsticks[i].onNext({});
      chopsticks[(i+1) % 3].onNext({});
    }, 1000);
    return 'philosopher ' + i + ' eating';
  };
};

var dining = Rx.Observable.when(
  hungry[0].and(chopsticks[0]).and(chopsticks[1]).thenDo(eat(0)),
  hungry[1].and(chopsticks[1]).and(chopsticks[2]).thenDo(eat(1)),
  hungry[2].and(chopsticks[2]).and(chopsticks[0]).thenDo(eat(2))
);

dining.subscribe(console.log.bind(console));

chopsticks[0].onNext({}); chopsticks[1].onNext({}); chopsticks[2].onNext({});

for (var i = 0; i < 3; i++) {
  hungry[0].onNext({}); hungry[1].onNext({}); hungry[2].onNext({});
}

Location

File:

• /src/core/linq/observable/when.js

Dist:

• rx.all.js
• rx.all.compat.js
• rx.joinpatterns.js

Prerequisites:

• rx.joinpatterns.js
• rx.js | rx.compat.js | rx.lite.js | rx.lite.compat.js

NPM Packages:

• rx

NuGet Packages:

• RxJS-All
• RxJS-JoinPatterns

Unit Tests:

• /tests/observable/when.js